Progressive commentators have been piling on Rick Santorum for a weirdly incoherent statement he made about the state of American history classes in America's colleges. Here's what he said:

"I was just reading something last night from the state of California. And the state of California universities -- I think it's seven or eight of the California system of universities -- don't even teach an American history course. It's not even available to be taught. Just to tell you how bad it's gotten in this country, where we're trying to disconnect the people from the root of who we are...."

The derision Santorum has received is well-deserved. He messed up the facts badly: 10 of the 11 UC campuses do teach US history (the only exception is UC San Francisco, which is exclusively a graduate-level health sciences campus and offers no humanities classes at all).

It also misses the point. It's not news when a conservative says something that was flat-out wrong, or when liberals take smug satisfaction in demonstrating that they are (as usual) factually right. But there was something else Santorum said in that statement that was newsworthy and important -- and in our zeal to debunk the facts, many progressives are completely missing it.

Last week, the New York Times published a widely discussed article updating an argument that progressive bloggers noticed a very long time ago. It's now well-understood that blue states generally export money to the federal government; and red states generally import it.

TPM published a great map showing exactly how this redistribution works: